Fabric covered buildings are well known wherein a plurality of supports, often made of tubing, are erected on a foundation base and held in spaced apart relationship by purlins connected between them. The structure is then covered with fabric, somewhat analogous to a tent. Such buildings are economical, fast and easy to erect and maintain, durable and easy to relocate. These features have made fabric covered buildings very popular, and led to demand for ever longer and wider buildings. However, these wider buildings are subject to much higher loads from wind, snow and so forth. The standard single member arch is unable to withstand these loads.
Truss arches, such as that shown in U.S. Pat. No. 5,269,106 to Stafford et al., have been utilized to provide the increased strength need for larger a fabric covered building, and in particular such a building wherein a single sheet of fabric is pulled over the framework and secured on each side. The Stafford patent teaches a truss arch for use in a building wherein the fabric covering takes the form of panels joined to each arch, thereby covering the area between a pair of spaced apart arches. The arch members are extruded channel members.
Fabric covered buildings are also known wherein a single piece of fabric is stretched over the top of a supporting frame, and secured by ropes and so forth. In this type of building it is very important to eliminate anything on the support structure and arches that might tear the fabric or provide a wear point as the fabric flexes due to wind and so forth.
Trusses are often manufactured of aluminum so that increased strength is available while keeping weight low and thereby contributing to ease and economy of erection and transport. Use of aluminum is, however, more expensive than using steel.